During anesthesia and in intensive care situations, it is standard practice to intubate the patient with a tube, introduced into the trachea, to facilitate pulmonary ventilation. Modern tracheal tubes now typically include an inflatable balloon or cuff near their distal end to occlude the air passageway and maintain respiration, and, secondarily, to provide barrier against aspirated substances. The inflatable cuff on a typical commercially available endotracheal tube is in the form of an oval or sphere-shaped balloon which permits these secretions to pool around the superior surface and, in some circumstances, pass by the balloon and into the tracheobronchial tree. While it is standard protocol to attempt suctioning of this surface, it is awkward and, done blindly, may result in the incorrect suctioning of the pharynx. In any case, the procedure is not effective in the ICU setting.
To ensure that proper suctioning occurs in an around the superior surface of the inflatable cuff, it is known in the art to provide a separate tube or lumen directed into this area. For example, U.S. Pat. No. 5,067,497 "Intubation Device with Adjustable Suction Means Above the Cuff" discloses a suction tube that runs along the main tube body, which is fixed with respect to the main tube except for an adjustable portion near the cuff to improve suctioning above a standard inflatable balloon. U.S. Pat. No. 5,143,062 "Endotracheal Tube Having Irrigation Means" also includes a suction inlet just above the proximal portion of the inflatable cuff.
U.S. Pat. No. 5,201,310 "Medico-Surgical Tube with Sealing Cuff and a Suction Lumen at the Top of the Cuff" includes a suction lumen extending along the tube and an opening through a suction aperture immediately adjacent the upper, proximal end of the cuff. The inflatable cuff is attached to the external surface of the tube by collars. The proximal collar is inverted within the inflatable portions of the cuff so that it does not extend beyond the inflatable portion and so that the maximum amount of secretions can be removed through the suction aperture.
U.S. Pat. No. 5,311,864, "Tracheas Evacuation and Transmittal Tube," shows a suction lumen disposed along the ramped portion of the inflatable balloon at its proximal end. U.S. Pat. No. 4,305,392 "Endotracheal Tube with Suction Device" includes an inflatable cuff and a suction chamber adjacent the upper side of the cuff. The suction chamber is in the shape of a bulge having four ports equally spaced around the periphery and facing upwardly. U.S. Pat. No. 4,502,482 "Endotracheal Tube Complex" includes a suction tube which fits into the main tube body to aspirate fluids from the lungs.
U.S. Pat. No. 4,637,389 "Tubular Device for Intubation" includes an expansible channel along the length of the tracheal tube with perforations into which a suction catheter may be guided for the removal and secretions and other substances which might accumulate around the tube. U.S. Pat. No. 4,840,173 "Endotracheal Tube Combination" includes combined dual passages to provide a ventilation tube and a suction tube. The suction passage terminates at the cuff with openings into the suction passage for secretions that might pool around the cuff.
Whether provided in the form of a separate lumen, tube, or a cavity to accept a separate tube, these references provide means for suctioning in and around a more or less conventional oval-shaped balloon, and although these references solve problems associated with the area in which suctioning should be carried out, they do not solve problems associated with effectively collecting aspirated substances in the first place which, if addressed, might reduce the frequency with which suctioning is required, perhaps avoiding the need for suctioning in critical care situations, and minimizing patient discomfort.
U.S. Pat. No. 4,979,505 to Cox discloses a low-pressure inflatable cuff for tracheal tube use taking the form of first and second paraboloid portions which are inverted with respect to one another to approximate an hourglass configuration. This shape is primarily designed to ameliorate the complications of the constant pressure of the inflatable cuff and decrease injury associated with prolonged intubation. Should aspiration occur, however, the fluids or particulate matter are trapped in the open reservoir created around the tube by the upper paraboloid shaped cuff, which has its open end oriented toward the larynx. Thus, this reference addresses the shape of an inflatable cuff on a tracheal tube to more effectively collect aspirated substances. However, two cuffs are required in this design, because the lower paraboloid is designed specifically for respiratory control, requiring the upper paraboloid to protect the pulmonary tree against aspiration and secretions. Moreover, while this reference makes no reference to the suctioning of fluids and particulate matter trapped within the reservoir of the upper paraboloid, it can be assumed that standard suctioning procedures are intended, in which case the problems associated with blindly positioning the suctioning tube in the correct spaces are neither addressed nor eliminated by this cuff design. As such, there remains a need for an endotracheal tube including a single inflatable cuff forming a collection basin in combination with means to provide suctioning precisely within this basin for an effective removal of substances collected therein.